Flexible diaphragm



Jan. 20, 1959 P. BAKER 2,869,585

FLEXIBLE DIAPHRAGM Filed Feb.l 15, 1954 INVENToR. Max P Baker 825m. www

His Affornev United States Patent FLEXIBLE DIAPHRAGM Max P. Baker, Dayton, Ohio, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware t Application Felimary 1s, 1954, serial No. 410,405 V4 claims. (ci. rs1-19s) edge is pressed into sealing engagement by a metallic p spring member that is intimately attached to the edge and body of said diaphragm.

Another object of the present invention is to bond .a

" metallic spring annulus` to one side of `a flexible diaphragm so theannulus will constantly maintain the center portionsof the diaphragm in contact with an actuating means and marginal edges thereof in sealing contact with wall portions of a chamber of a pump wherewith it is associated.` t

A further object of thel present invention is to provide a pump with a flexible diaphragm that` acts as a flexible wall for a chamber to vary the volume thereof when the diaphragm is flexed by a reciprocating plungenthat simultaneouslycontacts a central Aportion of the diaphragm and an annular metallic spring memberfthat extends to thel marginal edges of the diaphragm so that said edges will be pressed into sealing engagement with wall portions of the chamber by the annular member that is` coextensively bonded to the portions of the diaphragm which it contacts.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawing wherein a preferred embodiment of the present invention is clearly shown.

In the drawing:

Figure 1 in section shows a pump embodying a diaphragm according to the present invention.

Figure 2 is a plan view of the diaphragm taken in the direction of arrow 2 in Figure l.

Figure 3 is an elevational view of the diaphragm in Figure 2.

Figure 4 is a plan view of metallic spring member.

Figure 5 is a view along line 5.--5 of Figure 4.

Figure 6 is a sectional view along line 6-6 of Figure 2.

In the drawing the exible diaphragm 30 shown forms a flexible wall for a chamber 21 of a pump 20, and when flexed will vary the volume of a chamber 21 as a plunger 22, wherewith diaphragm 30 is in constant contact, is reciprocally moved by a suitable means such as an eccentric cam 23. The chamber 21 is formed between parts 24 and 26 of the pump 20. These parts l fluidis expelled through outlet 29 for each exure cycle of the diaphragm 30.

A clean out passage 31, formed in part4 26, may be used to bleed any air from chamber 21. This passage 31 is closed andsealed by a member 32 which forces a washer 33 into sealing contact with part 26 as the threads on member 32 are tightened in a threaded portion in part 26.

The plunger 22 is constantly maintained in Contact with an actuating mechanism 23 by a spring 34 that has one end seated against a spring seat formed on part t 24'and the other end biased against a spring seat 25 that is operatively carried by'the plunger 22.

The diaphragm 30, in the preferred embodiment, is preferably circular in shape, although any suitably sided polygonal shaped member might be used for a circular object is merely a polygonal object with an infinite number of sides. The diaphragm 30 is formed of a flexible material with a portion of the marginal edge curved to provide a feathered edge 36. This edge 36 is maintained in tight sealing engagement with a curved surface portion 42 of chamber 21 by a metal t annular member 38 which tightly forces the feathered edge 36 and an inclined outer marginal edge portion 40 of the diaphragm 30 into pressure contact with other portions of the curved surfaces 42.

The face 44 of diaphragm `30 adjacent the chamber 21 is preferably concave in shape to aid the flexing action `of the diaphragm 30. The diaphragm 30 also has a central enlarged convex or bulged portion 46` on the side of the diaphragm 30 remote from face 44. The enlarged portion 46 preferably hasits outer surface `rounded so that it will conform to the end of plunger 22 and preferably is of suicient size to embed a portion of the annular spring member 38 in the material of the diaphragm 30.

y Metallic member 38 is made of springy material and is preferably of frustro-conical shape. The contacting portions of member 38 are bonded to both 'the marginal edge 36 and an intermediate portion 48 of a diaphragm. The portion 48 is thinner than the central portion 46 of diaphragm 30 and substantially thicker than edge portion 36 and is located therebetween so the diaphragm 30 will have a proper` flexing action when it is moved by the plunger 22, which simultaneously engages the central portion 46 of diaphragm 30 and the inner annular portions of the metallic member 38.

The annular metallic spring member 38 may be of the Belleville spring type or of any other suitable construction so that it will properly llex when the plunger 22 exerts its flexing movement against member 3S and the enlarged portion 46 of diaphragm 30. it is to be noted, the travel of plunger 22 while it may be adjusted is limited so the shape of the metallic member ft'will not substantially invert during the travel of plunger 22. This condition will cause the flexible portions of the diaphragm 30 to closely follow the reciprocating movement of plunger 23 and thereby achieve the pumping action on the fluids in cylinder 21.

From the above it is manifest that the material of the diaphragm may be of any suitable exible material such as leather, impregnated cloth or suitable elastomers as synthetic rubbers such as butadiene styrene copolymers, butadiene acrylonitrile copolymers or natural rubbers, or suitable mixtures of the above, etc., and the member 38 may beof any suitable well known springy material such as Phosphor bronze, a springy organic plastic, etc.,4

assegno of a solid disc-like construction having finger-like em-` bossments extending either from the outer or inner peripheral portions, provided always that the spring member 3S applies the :force as exerted .bytheplungerl to the marginal edges 36 and di) of therdiaphragrn :3.0 against the wallportions of chamberllsothata positive sealing pressure is maintained .between ,the wall .of chamber 21 and .sealing portions -of thediaphragm 3,0,

Further the metallic vbacking member 38 may b e separated from-the `plunger 22 by `the material of Adiaphragm 36. This construction is within the scope of the present invention providing ,that the metal portions adjacent the center of the member 38 are within ,the `axial projection of rplunger `22, so that the y.pressure applied by the plunger 22 during the pumping stroke vwill be applied through member 35 on ithe marginal edge 36 of diaphragm 3@ and will be greatest when the tluid pressure in chamber V2li is at a maximum soithat a metered amount `of fluid under a substantially -high pressure will be .an inverted position, the travel of the plunger must not exceed the point where the `spring williail totconstantly `maintain `the diaphragm 3l) in engagement with the plunger 22. v

While theembodiment of the present invention as herein-disclosed constitutes aV preferred form, it is to be understood that Vother forms 'might rbc-adopted.

What isclarned is as follows: .1. In a ,pump having an elastomeric diaphragm, .a frusto-conically lshaped spring metal annulus surrounding a central portion of the diaphragm and having vatleast i one surface coextensively bonded to theperllheral portions .of elastomeric material forming said diaphragm and movable therewith and constantly resistingy movement of said `diaphragm from a normal position.

' coextensively bonded faces thereof.

2. An article of manufacture comprising: an elastomeric disc shaped body having marginal edges of a predetermined shape, and a tiexible metallic annulus of frustro-conical shape providing a backing for said body and extending to the marginal edges thereof and bonded to said body at the juxtaposed surface portions thereof.

3. An article of manufaeltlleincluding: a disc shaped elastomeric body having marginal Y,edges of a predetermined thickness, a central -portion of greater thickness .than tthe Vmarginal edges?, and an ,intermediate portion ioining tthe marginal edges and the center position, said intermediate portion having a thickness intermediatethe thickness ,of said edges andoenterportionand blending into 'the surfaces thereof, "anda metallic Vspring annulus constructed and arranged -to extend to the marginal edges of said body and apertured at the center portion thereof to embrace the center portion of said body and tothe body at the lj uxtaposed fsur- 4. A exible ywall for Aa chamber, #comprisingiin combination: an elastomeric disc shaped body portion having ymarginal edge lwithsurfaceportions curved to Lprovide a feathered edge, la ycentral portion'having acurved surface and-of ya greater thickness 'than the marginal edge portions, and -a portion intermediate said central and 'marginal edge'portions "havinga thickness intermediate said portions and blendingintoithe curved surface lpor- A-tions thereof, Band a metallic spring` annulus vhaving,

portions "thereof extending 'to the lfeathered edge portions lof Vsaid body and bonded Ito, the intermediate and "feathered edge portions of saidfbody at ythe juxtaposed surface portions thereof.

References Cited in thefilelofgths patent 

